Messages in this thread | | | Date | Thu, 14 Apr 2005 12:59:47 +0200 | From | Manfred Spraul <> | Subject | Re: [patch 1/9] GFP_ZERO fix |
| |
Andrew Morton wrote:
>Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > >> #define GFP_LEVEL_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS| \ >> - __GFP_COLD|__GFP_NOWARN|__GFP_REPEAT| \ >> - __GFP_NOFAIL|__GFP_NORETRY|__GFP_NO_GROW|__GFP_COMP) >> + __GFP_COLD|__GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL| \ >> + __GFP_NORETRY|__GFP_NO_GROW|__GFP_COMP|__GFP_ZERO) >> >> > >Passing GFP_ZERO into kmem_cache_alloc() is such a bizarre thing to do, >perhaps a BUG is the correct response. > >I guess it could be argued that the kmem_cache_alloc() callers "knows" that >the ctor will be zeroing out all the objects, but it would seem cleaner to >me to pass the "you should use GFP_ZERO" hint into kmem_cache_create() >rather than kmem_cache_alloc(). > > Right now, slab is not really suitable for GFP_ZERO: - if debug is enabled, then objects are definitively not 0-initialized. - if a ctor is used for zero initialization, then objects would have to be zeroed before kmem_cache_free: The ctor is only called at object creation, not before object reuse. But memset(,0,) just before free would be a bit silly.
Probably a BUG_ON or WARN_ON should be added into kmem_flagcheck() and into kmem_cache_create().
Should I write a patch? -- Manfred
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |